ANTLIA SII 3nm FAST ULTRA NARROWBAND FILTER

The Antlia SII 3nm FAST ultra narrowband filter boosts the contrast of emission nebulae and supernova remnants for professional results, even under a bright sky affected by light pollution. The FAST series of filters are designed for telescopes with a focal ratio between f/2.6 - f/3.6.

Blueshift data indicates that at a focal ratio of f/2.6, the angle of incidence of the light cone is 10° and its bandwidth shifts 2.2nm to shorter wavelengths. Therefore, the FAST 3nm ultra narrowband filters are designed to be pre-shifted by 1.2nm towards the longer (red) end in order to compensate for this blueshift and ensure high signal with telescopes which have fast focal ratios.

Using these highspeed SHO 3nm Pro narrowband filters for telescopes with focal ratios between f/2.6 and f/3.6 shows much stronger and more contrasted images compared to the standard non-FAST filters.

For optics with f-ratios slower than f/3.6, the standard 3nm Pro filters are recommended. Meanwhile, if you use optics faster than f/2.6, the 4.5nm EDGE filters will give better signal.

The 3.0 nm band pass is only 1% of the entire visible spectrum, increasing the signal to noise ratio and delivering high contrast images and extremely dark backgrounds. To even further enhance the contrast, and suppress the stray light and internal reflections, Antlia applies edge-blackening coating on each filter.

The maximum transmission of the Sulphur II line (671.6 nm) is above 90% and the transmission off band is only 0.001%. This is a value often undisclosed by other filter producers and it is critical to darken the sky background and minimise the halos around the stars.

Each filter is individually tested to ensure a high quality standard. The tight tolerance of the filters substrate assure a maximum deviance of ±0.05 from specifications making these filters parfocal.

The filter cuts off the ultraviolet and infrared light so there is no need to use the IR-cut filter.

DO NOT LOOK AT THE SUN WITH THE ANTLIA FILTERS. Serious eye damage will occur.  

Specifications

SII FAST filter transmission curve.